The script seems to be a few years old so I guess it's no longer updated or maintained ?

I also found a DNSBL script on these forums but that's also from 2004 and the needed files are no longer available.

I use RBL myself for my forums and they work pretty good so if there is a script that can use these blacklists to filter emails that would be great (even better would be an option to submit spammers to that blacklist so others benefit from it, I guess that's also something SpamCop.net does since the BNSBL script also checked there for spam).